Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/027—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds
  • G03F7/032—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds with binders
  • G03F7/033—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds with binders the binders being polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/146—Laser beam

Definitions

• the invention relates to a process for the production of heat-resistant structured layers based on epoxy resin by applying radiation-sensitive soluble polymers in the form of a layer or film to a substrate, irradiating the layer or film by negative templates with actinic light or by guiding a light, electron or laser. or ion beam, removing the non-irradiated layer or Film parts and optionally by subsequent annealing, and the use of these structured layers.
• Processes for producing structured layers based on heat-resistant polymers are known, for example, from German patent specification 2 308 830 and from European patent specifications 0 019 123 and 0 026 820.
• soluble photoreactive precursors of highly heat-resistant polymers are used for the photolithographic structuring and the structures produced therefrom are cyclized to highly heat-resistant structures in a subsequent annealing step.
• Temperatures up to 400 ° C are required for complete cyclization and removal of the cleavage products. This requires substrates that can withstand high thermal loads.
• epoxy-based substrates are used, among others, which can be subjected to a maximum thermal load of up to approx. 150 ° C / 1 h and which only have to withstand temperatures of approx. 280 ° C in the seconds range , at for example in soldering processes.
• solder resist used here for partial conductor track covering must meet similar thermal requirements, ie in this case polymers with a medium thermal resistance are required to cover the points on the circuit surface which are not intended to come into contact with the solder metal.
• the dry resists or screen printing varnishes based on epoxy and acrylate (still used for this purpose) meet the requirements of a solder mask, but only partially meet the increased requirements for dimensional accuracy in fine conductor technology with structures ⁇ 100 ⁇ m, as well as the required cycel strength. Photolithographic coating systems are required for this.
• the object of the invention is to design a method of the type mentioned in such a way that it is possible to produce dimensionally accurate, high-quality structured layers based on epoxy resin, in particular on circuit surfaces, in a single coating process, which also includes the extensive thermal and mecha withstand the stresses such as immersion soldering processes and also effectively and permanently protect the circuit surface against moisture and corrosion.
• the process cycle is to be shortened by short exposure, development and tempering times and thereby designed to be inexpensive.
• photopolymers in the form of addition products of olefinically unsaturated monoisocyanates with epoxides containing hydroxyl groups.
• the method according to the invention allows - within the framework of an inexpensive process flow - the production of finely structured protective and insulating layers for the semiconductor and circuit sector, which effectively and permanently protect the components and circuits sensitive to corrosion. It is particularly advantageous that the development process does not lead to loosening and thus no solder bridges occur in soldering processes.
• the method according to the invention not only fulfills the requirements regarding the dimensional accuracy of the structures produced, it also enables very high resolution in a wide layer thickness range with short development times.
• the photopolymers can advantageously be used together with light- or radiation-sensitive copolymerizable compounds.
• compounds containing acrylate and methacrylate groups are preferably used, in particular trimethylolpropane triacrylate and methacrylate and / or 1,4-butanediol dimethacrylate.
• compounds containing allyl groups for example diallyl and triallyl cyanurates, and N-substituted maleimides can also be used.
• Photoinitiators and / or sensitizers can also be used (see: "Industrie Chimique Belge", vol. 24, 1959, pages 739 to 764, and J.
• Suitable photoinitiators or sensitizers are, for example, benzoin ether, 4.4 ⁇ -bis (diethylamino) benzophenone, 2,6-bis (p-azidobenzylidene) -4-methylcyclohexanone, thioxanthones such as isopropylthioxanthone and acetophenone.
• adhesion promoters can advantageously be used in the method according to the invention.
• silanes such as vinyl triethoxysilane, vinyl tris ( ⁇ -methoxyethoxy) silane, ⁇ -methacryloxypropyl trimethoxysilane, ⁇ -glycidoxypropyl trimethoxysilane and ⁇ -aminopropyl triethoxysilane are used for this purpose.
• Hardeners such as are usually used for curing epoxy resins, are preferably added to the solutions of the photopolymers.
• Mineral fillers in particular those based on silicon dioxide and aluminum oxide, as well as others, can also advantageously be used in the solutions fillers used are added.
• photopolymers used in the process according to the invention are described in the simultaneously filed European patent application "Photopolymers based on epoxy resin", application number ......... (VPA 86 P 3326 E). These photopolymers generally have the following structure:
• N is between 1 and 20.
• R is an - optionally halogenated - divalent, ie difunctional radical of aromatic and / or aliphatic and / or cycloaliphatic, optionally having heteroatoms, and / or heterocyclic structure
• R1 is a divalent aliphatic radical
• R2 is an optionally halogen-substituted divalent aliphatic and / or cycloaliphatic radical
• R3 is hydrogen or an - optionally halogen-substituted - alkyl group
• R4 is an olefinically unsaturated group bonded via an aliphatic and / or cycloaliphatic and / or aromatic bridge, for example an allyl ether- or maleimide-containing group and in particular an - optionally substituted - (meth) acrylic ester-containing group.
• the photopolymers are preferably based on epoxy resins with aromatic partial structures.
• the aromatic partial structures can advantageously be halogenated, in particular brominated.
• the epoxides themselves preferably have one Epoxy equivalent weight between 600 and 6000, especially between 2400 and 4000.
• Preferred photopolymers are addition products of isocyanatoethyl methacrylate and epoxy resins having aromatic partial structures, which - optionally fluorinated - have isopropyl groups, or addition products of - optionally core-brominated - aromatic partial structures with epoxy resins with olefinically unsaturated monoisocyanates in the form of addition products and 2,4-diisocyanate methacrylate from 2,4-diisocyanate methacrylate from 2,4-diisocyanate methacrylate from 2,4-diisocyanate methacrylate from 2,4-diisocyanate methacrylate.
• Such photopolymers are exemplified in the following formulas (1) and (2).
• the structured layers according to the invention are produced in such a way that the photopolymer is applied to a substrate in the form of a layer or film and exposed to actinic light through a mask or by guiding a light, electron, laser or Ion beam is irradiated. Subsequently, the non-exposed or non-irradiated layer or film parts are detached or removed and the structured layers or relief structures obtained in this way are annealed if necessary.
• the photopolymer is advantageously applied to the substrate dissolved in an organic solvent.
• the concentration of the photopolymer in common solvents can be adjusted so that with known coating methods, such as spinning, dipping, spraying, pouring, knife coating, brushing or rolling, layer thicknesses of 0 , 01 to approximately 500 ⁇ m can be generated.
• coating methods such as spinning, dipping, spraying, pouring, knife coating, brushing or rolling, layer thicknesses of 0 , 01 to approximately 500 ⁇ m can be generated.
• the casting method such a method is known, for example, from European Patent 0 002 040
• knife coating and in particular electrostatic spray coating and spin coating at 300 to 10,000 revolutions / minute have been found to be suitable proven advantageous.
• spin speeds of 300 to 1500 are advantageous.
• the viscosity range of the coating solutions used for knife coating, spraying and the casting process is advantageously between 200 and 1500 mPa.s at 23 ° C.
• the photoresist layer applied to the substrate which preferably consists of printed circuit board material, glass, metal, plastic or semiconductors, can be freed from the solvent in a nitrogen or air stream at room temperature, preferably at temperatures from 50 to 80 ° C .; can also worked in a vacuum or dried with infrared radiators or on a heated plate.
• film parts are sufficient, depending on the composition and the layer thickness, exposure times between 5 and 400 s. After exposure, if necessary after an after-drying process, the unexposed parts are removed with organic solvents.
• the structured layers or relief structures produced by the method according to the invention are characterized by edge sharpness, high resolution, a crack-free homogeneous surface and a heat resistance which also withstands the thermal and mechanical stresses of a dip soldering process.
• the adhesion to the solder is very low, so that, as desired, no solder pearls get caught on the polymer layer.
• the structured layers produced according to the invention are elastic enough to pass cycle tests between -65 and + 125 ° C without cracking. Circuit surfaces covered with the structured layers show no trace corrosion in climate tests at 40 ° C and 92% humidity under voltage (100 V). Such layers are therefore - in addition to their use as solder masks - also effective and durable protective layers against the effects of moisture and harmful gases.
• the structured layers according to the invention are also suitable for the production of passivation layers on semiconductor components, of thin and thick film circuits, of solder protection layers on multilayer circuits, of insulating layers, because of the high purity due to the production as a component of layer circuits and of miniaturized protective and insulating layers on electrically conductive and / or semiconducting and / or insulating base materials, and generally for fine structuring of substrates and for structure transfer processes, such as wet and dry etching processes, electroless or galvanic metal deposition and vapor deposition processes, and as masks for ion implantation.
• these layers are suitable as insulating and protective layers in electrical engineering and in microelectronics, as well as damping compounds for surface acoustic wave filters, in particular television intermediate frequency filters, as orientation layers in liquid crystal displays and as a dielectric in multi-layer wiring.
• a photostructured layer treated with known commercially available fluxes shows a homogeneous crack-free surface after the solder bath test at 260 ° C. and 20 s immersion time. The solder rolls off the paint surface well.
• the filtered solution of the photoreactive epoxy resin is spun at 400 revolutions / minute onto a circuit board test plate with copper conductor tracks on the surface and then dried in a forced air oven at 70 ° C. for 1/2 hour.
• the thickness of the lacquer layer is then 50 ⁇ m.
• cyclohexanone as the developer with water being used as a stopper, is obtained after 35 s with sharp-edged structured layers which - after 30 minutes Curing at 150 ° C - its surface quality is not affected by cycling a hundred times between -65 and + 125 ° C.
• These layers also withstand splash and dip soldering processes at 260 ° C; the solder rolls off the surface.
• Moisture tests at 40 ° C and 92% humidity and under a voltage of 100 V show no corrosion in the conductor track areas covered with paint.
• a mixture of 23.6 parts by weight of pure 2-hydroxyethyl acrylate and 24.8 parts by weight of pure 2-hydroxyethyl methacrylate is slowly added dropwise to a solution of 66.8 parts by weight of pure 2,4-diisocyanatotoluene in 115 parts by weight of dichloromethane with stirring and exclusion of moisture. After 30 hours of reaction at room temperature, an isocyanate conversion of 98% is determined by titration.
• the solution of the photoreactive monoisocyanate obtained is combined with a solution of 98 parts by weight of the epoxy resin Araldit GT 6099 in 397 parts by weight of ⁇ -butyrolactone and with 0.22 parts by weight of dibutyltin dilaurate. After 24 hours of reaction at room temperature, 15 parts by weight of ethanol are added to the reaction solution. After another 24 hours, the coating solution is ready for use.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Non-Metallic Protective Coatings For Printed Circuits (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)
• Epoxy Resins (AREA)
• Polyurethanes Or Polyureas (AREA)
• Macromonomer-Based Addition Polymer (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=6309379

Family Applications (1)

Country Status (6)

Cited By (1)

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• 1987
  • 1987-08-28 EP EP87112572A patent/EP0259727A3/fr not_active Ceased
  • 1987-09-07 JP JP62223835A patent/JPS6381422A/ja active Pending
  • 1987-09-10 DK DK471987A patent/DK471987A/da not_active Application Discontinuation
  • 1987-09-11 KR KR870010083A patent/KR880004350A/ko not_active Ceased
  • 1987-09-11 FI FI873944A patent/FI873944A7/fi not_active Application Discontinuation
• 1989
  • 1989-04-11 US US07/336,578 patent/US4883730A/en not_active Expired - Fee Related

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